ABSTRACT
Reactive oxygen species such as H2O2 are believed to play a prominent role in the injury and loss of transport function that affect the intestinal epithelium in inflammatory conditions such as inflammatory bowel diseases. Defects in intestinal epithelial ion transport regulation contribute to dysbiosis and inflammatory phenotypes. We previously showed that H2O2 inhibits Ca2+-dependent Cl- secretion across intestinal epithelial cells (IECs) via a phosphatidylinositol 3-kinase (PI3K)- and extracellular signal-regulated kinase (ERK)-dependent mechanism that occurs, at least in part, through inhibition of the basolateral Na+-K+-2Cl- cotransporter NKCC1. NKCC1 governs Cl- entry into crypt IECs and thus plays a critical role in maintaining the driving force for Cl- secretion. Electrolyte transport consumes large amounts of cellular energy, and direct pharmacological activation of the cellular energy sensor AMP-activated protein kinase (AMPK) has been shown to inhibit a number of ion transport proteins. Here, we show that H2O2 activates AMPK in human IEC lines and ex vivo human colon. Moreover, we demonstrate that the inhibitory effect of H2O2 on Ca2+-dependent Cl- secretion and NKCC1 activity is AMPK-dependent. This inhibitory effect is associated with a physical interaction between AMPK and NKCC1, as well as increased phosphorylation (Thr212,217) of NKCC1, without causing NKCC1 internalization. These data identify a key role for AMPK-NKCC1 interaction as a point of convergence for suppression of colonic epithelial ion transport by inflammatory reactive oxygen species.NEW & NOTEWORTHY H2O2 inhibition of intestinal epithelial Ca2+-dependent Cl- secretion involves recruitment of AMP-activated protein kinase (AMPK) downstream of ERK and phosphatidylinositol 3-kinase signaling pathways, physical interaction of AMPK with the Na+-K+-2Cl- cotransporter NKCC1, and AMPK-dependent suppression of NKCC1-mediated electrolyte influx without causing NKCC1 internalization. It is intriguing that, in human intestinal epithelial cell lines and human colon, H2O2 activation of AMPK increased phosphorylation of NKCC1 residues required for promoting, not inhibiting, NKCC1 activity. These data identify an elevated complexity of AMPK regulation of NKCC1 in the setting of an inflammatory stimulus.
Subject(s)
Hydrogen Peroxide/metabolism , Inflammatory Bowel Diseases , Intestinal Mucosa/metabolism , Solute Carrier Family 12, Member 2/metabolism , AMP-Activated Protein Kinases , Carrier Proteins , Cells, Cultured , Humans , Inflammatory Bowel Diseases/immunology , Inflammatory Bowel Diseases/metabolism , Ion Transport/physiology , Phosphatidylinositol 3-Kinases/metabolism , Reactive Oxygen Species/metabolism , Signal TransductionABSTRACT
Transforming growth factor (TGF)-ß cytokines signal via a complex network of pathways to regulate proliferation, differentiation, adhesion, migration, and other functions in many cell types. A high percentage of colorectal tumors contain mutations that disrupt TGF-ß family member signaling. We review how TGF-ß family member signaling is altered during development of colorectal cancer, models of study, interaction of pathways, and potential therapeutic strategies.
Subject(s)
Colorectal Neoplasms/genetics , Colorectal Neoplasms/metabolism , Receptors, Transforming Growth Factor beta/genetics , Signal Transduction , Smad Proteins/genetics , Transforming Growth Factor beta/genetics , Transforming Growth Factor beta/metabolism , Activins/metabolism , Animals , Bone Morphogenetic Proteins/metabolism , Colorectal Neoplasms/immunology , Germ-Line Mutation , Homeostasis , Humans , Mice , Mice, Knockout , Receptors, Transforming Growth Factor beta/immunology , Smad Proteins/metabolismABSTRACT
OBJECTIVE: Colorectal cancer (CRC) incidence is higher in African Americans (AAs) compared with non-Hispanic whites (NHWs). A diet high in animal protein and fat is an environmental risk factor for CRC development. The intestinal microbiota is postulated to modulate the effects of diet in promoting or preventing CRC. Hydrogen sulfide, produced by autochthonous sulfidogenic bacteria, triggers proinflammatory pathways and hyperproliferation, and is genotoxic. We hypothesised that sulfidogenic bacterial abundance in colonic mucosa may be an environmental CRC risk factor that distinguishes AA and NHW. DESIGN: Colonic biopsies from uninvolved or healthy mucosa from CRC cases and tumour-free controls were collected prospectively from five medical centres in Chicago for association studies. Sulfidogenic bacterial abundance in uninvolved colonic mucosa of AA and NHW CRC cases was compared with normal mucosa of AA and NHW controls. In addition, 16S rDNA sequencing was performed in AA cases and controls. Correlations were examined among bacterial targets, race, disease status and dietary intake. RESULTS: AAs harboured a greater abundance of sulfidogenic bacteria compared with NHWs regardless of disease status. Bilophila wadsworthia-specific dsrA was more abundant in AA cases than controls. Linear discriminant analysis of 16S rRNA gene sequences revealed five sulfidogenic genera that were more abundant in AA cases. Fat and protein intake and daily servings of meat were significantly higher in AAs compared with NHWs, and multiple dietary components correlated with a higher abundance of sulfidogenic bacteria. CONCLUSIONS: These results implicate sulfidogenic bacteria as a potential environmental risk factor contributing to CRC development in AAs.
Subject(s)
Adenocarcinoma/microbiology , Black or African American , Colon/microbiology , Colorectal Neoplasms/microbiology , Intestinal Mucosa/microbiology , Sulfur-Reducing Bacteria/isolation & purification , White People , Adenocarcinoma/ethnology , Adenocarcinoma/etiology , Adult , Aged , Case-Control Studies , Chicago , Colorectal Neoplasms/ethnology , Colorectal Neoplasms/etiology , Diet/adverse effects , Dietary Fats/adverse effects , Dietary Proteins/adverse effects , Female , Health Status Disparities , Humans , Male , Middle Aged , Prospective Studies , Real-Time Polymerase Chain Reaction , Risk FactorsABSTRACT
Sporadic colorectal cancer (CRC) is a somatic genetic disease in which pathogenesis is influenced by the local colonic environment and the patient's genetic background. Consolidating the knowledge of genetic and epigenetic events that occur with initiation, progression, and metastasis of sporadic CRC has identified some biomarkers that might be utilized to predict behavior and prognosis beyond staging, and inform treatment approaches. Modern next-generation sequencing of sporadic CRCs has confirmed prior identified genetic alterations and has classified new alterations. Each patient's CRC is genetically unique, propelled by 2-8 driver gene alterations that have accumulated within the CRC since initiation. Commonly observed alterations across sporadic CRCs have allowed classification into a (1) hypermutated group that includes defective DNA mismatch repair with microsatellite instability and POLE mutations in â¼15%, containing multiple frameshifted genes and BRAF(V600E); (2) nonhypermutated group with multiple somatic copy number alterations and aneuploidy in â¼85%, containing oncogenic activation of KRAS and PIK3CA and mutation and loss of heterozygosity of tumor suppressor genes, such as APC and TP53; (3) CpG island methylator phenotype CRCs in â¼20% that overlap greatly with microsatellite instability CRCs and some nonhypermutated CRCs; and (4) elevated microsatellite alterations at selected tetranucleotide repeats in â¼60% that associates with metastatic behavior in both hypermutated and nonhypermutated groups. Components from these classifications are now used as diagnostic, prognostic, and treatment biomarkers. Additional common biomarkers may come from genome-wide association studies and microRNAs among other sources, as well as from the unique alteration profile of an individual CRC to apply a precision medicine approach to care.
Subject(s)
Colorectal Neoplasms/genetics , Gene Expression Regulation, Neoplastic , Genetic Markers , Genome-Wide Association Study/methods , CpG Islands , DNA Methylation , Genetic Predisposition to Disease , Humans , MicroRNAs , Microsatellite Instability , Mutation , PrognosisABSTRACT
BACKGROUND: Understanding cell signaling pathways that contribute to metastatic colon cancer is critical to risk stratification in the era of personalized therapeutics. Here, we dissect the unique involvement of mitogenic pathways in a TGFß or activin-induced metastatic phenotype of colon cancer. METHOD: Mitogenic signaling/growth factor receptor status and p21 localization were correlated in primary colon cancers and intestinal tumors from either AOM/DSS treated ACVR2A (activin receptor 2) -/- or wild type mice. Colon cancer cell lines (+/- SMAD4) were interrogated for ligand-induced PI3K and MEK/ERK pathway activation and downstream protein/phospho-isoform expression/association after knockdown and pharmacologic inhibition of pathway members. EMT was assessed using epithelial/mesenchymal markers and migration assays. RESULTS: In primary colon cancers, loss of nuclear p21 correlated with upstream activation of activin/PI3K while nuclear p21 expression was associated with TGFß/MEK/ERK pathway activation. Activin, but not TGFß, led to PI3K activation via interaction of ACVR1B and p85 independent of SMAD4, resulting in p21 downregulation. In contrast, TGFß increased p21 via MEK/ERK pathway through a SMAD4-dependent mechanism. While activin induced EMT via PI3K, TGFß induced EMT via MEK/ERK activation. In vivo, loss of ACVR2A resulted in loss of pAkt, consistent with activin-dependent PI3K signaling. CONCLUSION: Although activin and TGFß share growth suppressive SMAD signaling in colon cancer, they diverge in their SMAD4-independent pro-migratory signaling utilizing distinct mitogenic signaling pathways that affect EMT. p21 localization in colon cancer may determine a dominant activin versus TGFß ligand signaling phenotype warranting further validation as a therapeutic biomarker prior to targeting TGFß family receptors.
Subject(s)
Activins/metabolism , Colonic Neoplasms/metabolism , Receptors, Transforming Growth Factor beta/metabolism , Activin Receptors, Type II/genetics , Activin Receptors, Type II/metabolism , Activins/genetics , Animals , Blotting, Western , Cell Line, Tumor , Colonic Neoplasms/genetics , Immunohistochemistry , Immunoprecipitation , In Vitro Techniques , Mice , Mice, Knockout , Phosphatidylinositol 3-Kinases/genetics , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins p21(ras)/genetics , Proto-Oncogene Proteins p21(ras)/metabolism , Receptors, Transforming Growth Factor beta/geneticsSubject(s)
Academic Medical Centers/standards , Academic Success , Benchmarking/standards , Education, Medical/standards , Gastroenterology/education , Gastroenterology/standards , Quality Indicators, Health Care/standards , Humans , National Institutes of Health (U.S.)/standards , Research Support as Topic/standards , United States , Workplace/standardsABSTRACT
Acute Pancreatitis (AP) is associated with high mortality and current treatment options are limited to supportive care. We found that blockade of activin A (activin) in mice improves outcomes in two murine models of AP. To test the hypothesis that activin is produced early in response to pancreatitis and is maintained throughout disease progression to stimulate immune cells, we first performed digital spatial profiling (DSP) of human chronic pancreatitis (CP) patient tissue. Then, transwell migration assays using RAW264.7 mouse macrophages and qPCR analysis of "neutrophil-like" HL-60 cells were used for functional correlation. Immunofluorescence and western blots on cerulein-induced pancreatitis samples from pancreatic acinar cell-specific Kras knock-in (Ptf1aCreER™; LSL-KrasG12D) and functional WT Ptf1aCreER™ mouse lines mimicking AP and CP to allow for in vivo confirmation. Our data suggest activin promotes neutrophil and macrophage activation both in situ and in vitro, while pancreatic activin production is increased as early as 1 h in response to pancreatitis and is maintained throughout CP in vivo. Taken together, activin is produced early in response to pancreatitis and is maintained throughout disease progression to promote neutrophil and macrophage activation.
Subject(s)
Activins , Cell Movement , Macrophages , Neutrophil Activation , Pancreatitis , Signal Transduction , Animals , Activins/metabolism , Mice , Humans , Macrophages/metabolism , Macrophages/immunology , Pancreatitis/metabolism , Pancreatitis/pathology , Neutrophils/metabolism , Neutrophils/immunology , Disease Models, Animal , RAW 264.7 Cells , Macrophage Activation , HL-60 Cells , Pancreatitis, Chronic/metabolism , Pancreatitis, Chronic/pathology , MaleABSTRACT
Histone variant macroH2A1 has two splice isoforms, macroH2A1.1 and macroH2A1.2, with tissue- and cell-specific expression patterns. Although macroH2A1.1 is mainly found in differentiated, nonproliferative tissues, macroH2A1.2 is more generally expressed, including in tissues with ongoing cell proliferation. Consistently, studies in breast and lung cancer have demonstrated a strong correlation between macroH2A1.1 levels and proliferation, which is not the case for macroH2A1.2. This is the first study to assess the differential regulation and predictive potential of macroH2A1 isoforms in colon cancer. We found that macroH2A1.1 mRNA was down-regulated in primary colorectal cancer samples compared to matched normal colon tissue, whereas macroH2A1.2 was up-regulated. At the protein level, down-regulation of macroH2A1.1 correlated significantly with patient outcome (P = 0.0012), and loss of macroH2A1.1 was associated with a worse outcome. Over the course of Caco-2 cell differentiation, macroH2A1.1 was up-regulated at both the RNA and protein levels, whereas macroH2A1.2 was slightly down-regulated at the RNA level and stable at the protein level. These changes were accompanied by an antiproliferative phenotype exhibiting features of cellular senescence. Loss of macroH2A1.1 in vitro was characterized by a phenotype associated with cell growth and metastasis. These data demonstrate that macroH2A1 isoforms are differentially regulated in colon cancer, reflecting the degree of cellular differentiation. Notably, macroH2A1.1 expression predicts survival in colon cancer, thus identifying macroH2A1.1 as a novel colon cancer biomarker.
Subject(s)
Biomarkers, Tumor/biosynthesis , Colonic Neoplasms/metabolism , Gene Expression Regulation, Neoplastic/physiology , Histones/biosynthesis , Biomarkers, Tumor/genetics , Caco-2 Cells , Cell Cycle/genetics , Cell Differentiation/genetics , Cellular Senescence/genetics , Colonic Neoplasms/genetics , Colonic Neoplasms/pathology , Down-Regulation , Gene Knockdown Techniques , Histones/genetics , Humans , Neoplasm Metastasis , Neoplasm Proteins/biosynthesis , Neoplasm Proteins/genetics , Prognosis , Protein Isoforms/biosynthesis , Protein Isoforms/genetics , RNA, Messenger/genetics , RNA, Neoplasm/genetics , RNA, Small Interfering/genetics , Real-Time Polymerase Chain Reaction/methods , Reverse Transcriptase Polymerase Chain Reaction/methods , Up-RegulationABSTRACT
The purpose of this project was to describe the structure and outcomes of a colorectal cancer screening program at CommunityHealth, the largest free health clinic in Illinois. We conducted a retrospective observational study using administrative clinical data from 2006 to 2011. A total of 4,026 patients were eligible for colorectal cancer screening of which 2,418 (60.0 %) completed fecal occult blood testing (FOBT). Subsequently, 1,657 patients had negative FOBT results and 1,365 patients underwent on-site flexible sigmoidoscopy. Over 90 % of patients had never had a prior screening examination. A majority of patients were female (61.7 %) and self-identified as Mexican (37.5 %) or Polish (28.2 %). A total of 203 biopsies were performed resulting in the detection of 69 adenomas (5.0 %) and 1 adenocarcinoma (0.1 %). A comprehensive colorectal cancer screening program was successfully implemented in a large community health center serving a population of diverse racial and ethnic backgrounds without prior access to screening. This program could serve as model for colorectal cancer screening in diverse, low resource communities.
Subject(s)
Colorectal Neoplasms/diagnosis , Early Detection of Cancer/methods , Medically Underserved Area , Adenocarcinoma/diagnosis , Adenoma/diagnosis , Chicago/epidemiology , Community Health Services/methods , Community Health Services/organization & administration , Ethnicity/statistics & numerical data , Female , Humans , Male , Middle Aged , Occult Blood , Outcome and Process Assessment, Health Care , Retrospective Studies , SigmoidoscopyABSTRACT
OBJECTIVE: Severe acute pancreatitis (SAP), pancreatic inflammation leading to multiorgan failure, is associated with high morbidity and mortality. There is a critical need to identify novel therapeutic strategies to improve clinical outcomes for SAP patients. MATERIALS AND METHODS: A comprehensive literature review was performed to identify current clinical strategies, known molecular pathophysiology, and potential therapeutic targets for SAP. RESULTS: Current clinical approaches focus on determining which patients will likely develop SAP. However, therapeutic options are limited to supportive care and fluid resuscitation. The application of a novel 5-cytokine panel accurately predicting disease outcomes in SAP suggests that molecular approaches will improve impact of future clinical trials in AP. CONCLUSIONS: Inflammatory outcomes in acute pancreatitis are driven by several unique molecular signals, which compound to promote both local and systemic inflammation. The identification of master cytokine regulators is critical to developing therapeutics, which reduce inflammation through several mechanisms.
Subject(s)
Pancreatitis , Humans , Pancreatitis/genetics , Pancreatitis/therapy , Acute Disease , Inflammation/therapy , Fluid Therapy , CytokinesABSTRACT
The prostone analog, lubiprostone, is approved to manage constipation-predominant irritable bowel syndrome. Lubiprostone also protects intestinal mucosal barrier function in animal models of colitis. The aim of this study was to determine if lubiprostone improves barrier properties in isolated colonic biopsies from Crohn's disease (CD) and ulcerative colitis (UC) patients. Sigmoid colon biopsies from healthy subjects, CD and UC patients in remission, and CD patients with active disease were mounted in Ussing chambers. Tissues were treated with lubiprostone or vehicle to determine the effects on transepithelial electrical resistance (TER), FITC-dextran 4kD (FD4) permeability, and electrogenic ion transport responses to forskolin and carbachol. Localization of the tight junction protein, occludin, was determined by immunofluorescence. Lubiprostone significantly increased ion transport across control, CD and UC remission biopsies but not active CD. Lubiprostone selectively improved TER in both CD remission and active disease biopsies but not in control or UC biopsies. The improved TER was associated with increased membrane localization of occludin. Lubiprostone selectively improved barrier properties of biopsies from CD patients vs. UC and independent of an ion transport response. These data indicate that lubiprostone has potential efficacy in improving mucosal integrity in Crohn's disease.
ABSTRACT
We have shown that activin A (activin), a TGF-ß superfamily member, has pro-metastatic effects in colorectal cancer (CRC). In lung cancer, activin activates pro-metastatic pathways to enhance tumor cell survival and migration while augmenting CD4+ to CD8+ communications to promote cytotoxicity. Here, we hypothesized that activin exerts cell-specific effects in the tumor microenvironment (TME) of CRC to promote anti-tumoral activity of immune cells and the pro-metastatic behavior of tumor cells in a cell-specific and context-dependent manner. We generated an Smad4 epithelial cell specific knockout (Smad4-/-) which was crossed with TS4-Cre mice to identify SMAD-specific changes in CRC. We also performed IHC and digital spatial profiling (DSP) of tissue microarrays (TMAs) obtained from 1055 stage II and III CRC patients in the QUASAR 2 clinical trial. We transfected the CRC cells to reduce their activin production and injected them into mice with intermittent tumor measurements to determine how cancer-derived activin alters tumor growth in vivo. In vivo, Smad4-/- mice displayed elevated colonic activin and pAKT expression and increased mortality. IHC analysis of the TMA samples revealed increased activin was required for TGF-ß-associated improved outcomes in CRC. DSP analysis identified that activin co-localization in the stroma was coupled with increases in T-cell exhaustion markers, activation markers of antigen presenting cells (APCs), and effectors of the PI3K/AKT pathway. Activin-stimulated PI3K-dependent CRC transwell migration, and the in vivo loss of activin lead to smaller CRC tumors. Taken together, activin is a targetable, highly context-dependent molecule with effects on CRC growth, migration, and TME immune plasticity.
ABSTRACT
OBJECTIVES: A personal or family history of colorectal adenomas increases the risk of colorectal cancer (CRC). We aimed to compare physicians' communication with polyp patients vs. non-polyp patients, assess whether polyps or CRC family history were associated with physician-patient communication, and describe patients' disclosure of colonoscopy and polyp diagnosis to their relatives. METHODS: Four hundred nine patients completed an online survey regarding physician-patient communication of colonoscopy results, perceived personal and familial risk of polyps and CRC, and disclosure of colonoscopy results to relatives. RESULTS: Six percent of participants reported that their physicians discussed familial risks. Polyp diagnosis and family history predicted physician-patient discussions about familial CRC risks. Polyp diagnosis predicted physician-patient discussions of future surveillance. Twenty-two percent of patients told none of their relatives that they had a colonoscopy. Family history, gender, and education were associated with patient-family communication. CONCLUSIONS: There is room for improvement in physician-patient and patient-family communication following colonoscopy.
Subject(s)
Colonic Polyps/diagnosis , Colonoscopy , Colorectal Neoplasms/diagnosis , Communication , Family , Physician-Patient Relations , Female , Health Care Surveys , Humans , Male , Middle AgedABSTRACT
Metastasis accounts for the majority of cancer-related deaths. Accurate prediction of metastatic potential of tumors has been elusive, and the search for clinically useful markers continues. We previously reported that GIV/Girdin triggers tumor cell migration by virtue of a C-terminal guanine-nucleotide exchange factor motif that activates Gαi. Here we identify GIV as a metastasis-related protein whose full-length transcript (GIV-fl) is expressed exclusively in highly invasive colon, breast, and pancreatic carcinoma cells and not in their poorly invasive counterparts. A prospective, exploratory biomarker study conducted on a cohort of 56 patients with stage II colorectal cancer revealed a significant correlation between GIV-fl expression in tumor epithelium and shortened metastasis-free survival. Survival rate for patients with GIV-fl-positive tumors is significantly reduced compared with the patients with GIV-fl-negative tumors [P<0.0001; hazard ratio=0.076; CI=0.052-0.30 (95%)]. At the 5-yr mark, survival is 100% in the GIV-fl-negative group and 62 ± 9% (mean±SE; P=6×10(-5)) in the GIV-fl-positive group. Furthermore, GIV-fl expression predicts a risk of mortality independent of the microsatellite stability status, a well-established prognosticator of colorectal cancers. We conclude that GIV-fl is a novel metastasis-related protein and an independent adverse prognosticator that may serve as a useful adjunct to traditional staging strategies in colorectal carcinoma.
Subject(s)
Colonic Neoplasms/metabolism , Colonic Neoplasms/pathology , Gene Expression Regulation, Neoplastic/physiology , Microfilament Proteins/metabolism , Vesicular Transport Proteins/metabolism , Biomarkers, Tumor , Carcinoma/metabolism , Cell Line, Tumor , Humans , Immunohistochemistry , Liver Neoplasms/secondary , Microfilament Proteins/genetics , Neoplasm Invasiveness , Neoplasm Metastasis , Prognosis , Vesicular Transport Proteins/geneticsABSTRACT
BACKGROUND AND OBJECTIVES: Colorectal tumors are often observed with tumor infiltrating lymphocytes, presumably as a host-immune response, and patterns may segregate by types of genomic instability. Microsatellite unstable (MSI) colorectal cancers contain a pronounced lymphocyte reaction that can pathologically identify these tumors. Colorectal tumors with elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) have not been examined for lymphocyte patterns. METHODS: We evaluated a 108-person cohort with 24 adenomas and 84 colorectal cancers for MSI and EMAST. Immunohistochemical detection of CD4+ and CD8+ T cell infiltration were performed. Prognostic relevance was assessed by survival analysis. RESULTS: CD8+ T cell infiltration in the tumor cell nest (p = 0.013) and tumor stroma (p = 0.004) were more prominent in moderately and poorly differentiated adenocarcinoma than in adenoma and well-differentiated adenocarcinoma. CD8+ T cells in the tumor cell nest (p = 0.002) and tumor stroma (p = 0.009) were at higher density in tumors with ulcerating features compared to tumors with a sessile or polypoid appearance. MSI-H tumors showed a higher density of CD8+ T cell infiltrations in tumor cell nests (p = 0.003) and tumor stroma (p = 0.001). EMAST-positive tumors showed a higher density of CD8+ T cell infiltrations than EMAST-negative tumors both in tumor cell nest (p = 0.027) and in tumor stroma (p = 0.003). These changes were not observed with CD4+ T lymphocytes. There was no difference in cancer patient survival based on density of CD8+ cells. CONCLUSIONS: CD8+ T lymphocytes, but not CD4+ cells, were increased in tumor cell nests and the tumor stroma in both MSI and EMAST tumors, and showed higher infiltration in ulcerated tumors. CD8+ T lymphocyte infiltration is associated with both EMAST and MSI patterns, and increases with histological advancement.
Subject(s)
Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Lymphocytes, Tumor-Infiltrating/pathology , Microsatellite Instability , Microsatellite Repeats/genetics , Adenocarcinoma/genetics , Adenocarcinoma/pathology , Adenoma/genetics , Adenoma/pathology , CD4-CD8 Ratio , CD4-Positive T-Lymphocytes/pathology , CD8-Positive T-Lymphocytes/pathology , Cell Differentiation , Cohort Studies , Humans , Retrospective StudiesABSTRACT
BACKGROUND: Paraxial protocadherin (PAPC) plays a crucial role in morphogenetic movements during gastrulation and somitogenesis in mouse, zebrafish and Xenopus. PAPC influences cell-cell adhesion mediated by C-Cadherin. A putative direct adhesion activity of PAPC is discussed. PAPC also promotes cell elongation, tissue separation and coordinates cell mass movements. In these processes the signaling function of PAPC in activating RhoA/JNK and supporting Wnt-11/PCP by binding to frizzled 7 (fz7) is important. RESULTS: Here we demonstrate by loss of function experiments in Xenopus embryos that PAPC regulates another type of morphogenetic movement, the invagination of the ear placode. Knockdown of PAPC by antisense morpholinos results in deformation of the otic vesicle without altering otocyst marker expression. Depletion of PAPC could be rescued by full-length PAPC, constitutive active RhoA and by the closely related PCNS but not by classical cadherins. Also the cytoplasmic deletion mutant M-PAPC, which influences cell adhesion, does not rescue the PAPC knockdown. Interestingly, depletion of Wnt5a or Ror2 which are also expressed in the otocyst phenocopies the PAPC morphant phenotype. CONCLUSIONS: PAPC signaling via RhoA and Wnt5a/Ror2 activity are required to keep cells aligned in apical-basal orientation during invagination of the ear placode. Since neither the cytoplasmic deletion mutant M-PAPC nor a classical cadherin is able to rescue loss of PAPC we suggest that the signaling function of the protocadherin rather than its role as modulator of cell-cell adhesion is required during invagination of the ear placode.
Subject(s)
Cadherins/metabolism , Ear/embryology , Morphogenesis/physiology , Receptor Tyrosine Kinase-like Orphan Receptors/metabolism , Signal Transduction/physiology , Wnt Proteins/metabolism , Xenopus Proteins/metabolism , Xenopus laevis/anatomy & histology , Xenopus laevis/embryology , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Animals , Cadherins/genetics , Dishevelled Proteins , Ear/abnormalities , Ear/anatomy & histology , Embryo, Nonmammalian/anatomy & histology , Embryo, Nonmammalian/physiology , Gene Knockdown Techniques , Oligonucleotides, Antisense/genetics , Phenotype , Phosphoproteins/genetics , Phosphoproteins/metabolism , Protocadherins , Receptor Tyrosine Kinase-like Orphan Receptors/genetics , Receptors, G-Protein-Coupled/genetics , Receptors, G-Protein-Coupled/metabolism , Wnt Proteins/genetics , Wnt-5a Protein , Xenopus Proteins/genetics , Xenopus laevis/physiology , rhoA GTP-Binding Protein/genetics , rhoA GTP-Binding Protein/metabolismABSTRACT
BACKGROUND & AIMS: Elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) occurs during microsatellite instability (MSI) that is not associated with major defects in DNA mismatch repair (MMR) but rather the reduced (heterogenous) expression of the MMR protein hMSH3; it occurs in sporadic colorectal tumors. We examined the timing of development of EMAST during progression of colorectal neoplasias and looked for correlations between EMAST and clinical and pathology features of tumors. METHODS: We evaluated tumor samples from a cohort of patients that had 24 adenomas and 84 colorectal cancers. EMAST were analyzed after DNA microdissection of matched normal and tumor samples using the polymorphic tetranucleotide microsatellite markers MYCL1, D9S242, D20S85, D8S321, and D20S82; data were compared with clinical and pathology findings. Traditional MSI analysis was performed and hMSH3 expression was measured. RESULTS: Moderately differentiated adenocarcinomas and poorly differentiated adenocarcinomas had higher frequencies of EMAST (56.9% and 40.0%, respectively) than well-differentiated adenocarcinomas (12.5%) or adenomas (33.3%) (P = .040). In endoscopic analysis, ulcerated tumors had a higher frequency of EMAST (52.3%) than flat (44.0%) or protruded tumors (20.0%) (P = .049). In quantification, all tumors with >3 tetranucleotide defects lost MSH3 (>75% of cells); nuclear heterogeneity of hMSH3 occurred more frequently in EMAST-positive (40.0%) than in EMAST-negative tumors (13.2%) (P = .010). CONCLUSIONS: EMAST is acquired during progression of adenoma and well-differentiated carcinomas to moderately and poorly differentiated carcinomas; it correlates with nuclear heterogeneity for hMSH3. Loss of hMSH3 corresponds with multiple tetranucleotide frameshifts. The association between EMAST and ulcerated tumors might result from increased inflammation.
Subject(s)
Colorectal Neoplasms/genetics , DNA, Neoplasm/genetics , DNA-Binding Proteins/genetics , Gene Expression Regulation, Neoplastic , Microsatellite Repeats/genetics , Base Pair Mismatch , Colonoscopy , Colorectal Neoplasms/metabolism , Colorectal Neoplasms/pathology , DNA-Binding Proteins/metabolism , Female , Humans , Immunohistochemistry , Male , Middle Aged , MutS Homolog 3 Protein , Polymerase Chain ReactionABSTRACT
Colorectal cancer (CRC) remains the third most commonly diagnosed cancer and the third leading cause of cancer-related death in the USA. CRC can be prevented through regular screening and removal of precancerous polyps. However, roughly one third of eligible adults in the USA are not up to date with recommended CRC screening. To increase timely CRC screening uptake in the USA, in 2014, the National Colorectal Cancer Roundtable (NCCRT) launched 80% by 2018. This multilevel effort involved more than 1,500 pledged organizations targeting patients, providers, health care systems, and policymakers to increase U.S. CRC screening rates to 80% by 2018. Concurrent with this campaign, between 2012 and 2018, CRC screening rates increased nationwide by 3.6% from 65.2% to 68.8%, meaning that about 9.3 million more U.S. adults are being screened. NCCRT attributes these successes to widespread implementation of center- and system-wide evidence-based interventions to increase screening uptake, including direct patient communication, provider reminders via electronic health records, and patient navigation, among others. Moving beyond 2018, NCCRT has rebranded the initiative as the 80% Pledge and has since identified several targeted campaigns, including increased outreach to Hispanics, Latinos, and Asians, whose CRC screening uptake remains less than 50%; encouragement of Medicaid outreach activities around CRC screening in all 50 states; and advocacy for screening right at 50 years of age. Society of Behavioral Medicine continues to support NCCRT and encourages policymakers to do the same by taking legislative action to assure funding for Medicaid outreach, research innovations, and clinical quality improvement that supports the 80% Pledge.